Problem: Apply the distributive property to factor out the greatest common factor. $27-18r =$
Answer: $ 9$ is the greatest common factor of $27$ and $18r$. $\phantom{=}27-18r$ $={9}\cdot3-{9}\cdot 2r$ $={9}(3-2r)~~~~~~~~$ Apply the distributive property. The answer: $ {9}(3-2r) $